Esketamine
Esketamine, sold under the brand names Ketanest among others, is a medication used as a general anesthetic and for treatment-resistant depression. Esketamine is used as a nasal spray or by injection into a vein.
Esketamine acts primarily as a non-competitive N-methyl-D-aspartate receptor antagonist. It also acts to some extent as a dopamine reuptake inhibitor but, unlike ketamine, does not interact with the sigma receptors. The compound is the S enantiomer of ketamine, which is an anesthetic and dissociative similarly. It is unknown whether its antidepressant action is superior, inferior or equal to racemic ketamine and its opposite enantiomer, arketamine, which are both being investigated for the treatment of depression.
Esketamine was introduced for medical use in 1997. In 2019, it was approved for use with other antidepressants, for the treatment of depression in adults in the United States. The cost of the nasal spray as of 2019 will be US$4,700 to $6,800 for the first month.
Medical uses
Anesthesia
Esketamine is a general anesthetic and is used for similar indications as ketamine. Such uses include induction of anesthesia in high-risk patients such as those with hemorrhagic shock, anaphylactic shock, septic shock, severe bronchospasm, severe hepatic insufficiency, cardiac tamponade, and constrictive pericarditis; anesthesia in caesarian section; use of multiple anesthetics in burns; and as a supplement to regional anesthesia with incomplete nerve blocks.Depression
Similarly to ketamine, esketamine appears to be a rapid-acting antidepressant. It received a breakthrough designation from the for treatment-resistant depression in 2013 and major depressive disorder with accompanying suicidal ideation in 2016. The medication was studied for use in combination with an antidepressant in people with TRD who had been unresponsive to treatment; six phase III clinical trials for this indication were conducted in 2017. It is available as a nasal spray.In February 2019, an outside panel of experts recommended that the FDA approve the nasal spray version of esketamine, provided that it be given in a clinical setting, with people remaining on site for at least two hours after. The reasoning for this requirement is that trial participants temporarily experienced sedation, visual disturbances, trouble speaking, confusion, numbness, and feelings of dizziness during immediately after.
In January 2020, esketamine was rejected by the National Health Service of Great Britain. NHS questioned the benefits and claimed that it was too expensive. People who have been already using the medication were allowed to complete treatment if their doctors consider this necessary.
Side effects
Most common side effects when used in those with treatment resistant depression include dissociation, dizziness, nausea, sleepiness, anxiety, and increased blood pressure.Pharmacology
Esketamine is approximately twice as potent as an anesthetic as racemic ketamine. It is eliminated from the human body more quickly than arketamine or racemic ketamine, although arketamine slows its elimination.A number of studies have suggested that esketamine has a more medically useful pharmacological action than arketamine or racemic ketamine but, in mice, that the rapid antidepressant effect of arketamine was greater and lasted longer than that of esketamine.. The usefulness of arketamine over eskatamine has been supported by other researchers.
Esketamine inhibits dopamine transporters eight times more than arketamine. This increases dopamine activity in the brain. At doses causing the same intensity of effects, esketamine is generally considered to be more pleasant by patients. Patients also generally recover mental function more quickly after being treated with pure esketamine, which may be a result of the fact that it is cleared from their system more quickly. This is however in contradiction with R-ketamine being devoid of psychotomimetic side effects.
Unlike arketamine, esketamine does not bind significantly to sigma receptors. Esketamine increases glucose metabolism in frontal cortex, while arketamine decreases glucose metabolism in the brain. This difference may be responsible for the fact that esketamine generally has a more dissociative or hallucinogenic effect while arketamine is reportedly more relaxing. However, another study found no difference between racemic and -ketamine on the patient's level of vigilance. Interpretation of this finding is complicated by the fact that racemic ketamine is 50% -ketamine.
History
Esketamine was introduced for medical use as an anesthetic in Germany in 1997, and was subsequently marketed in other countries. In addition to its anesthetic effects, the medication showed properties of being a rapid-acting antidepressant, and was subsequently investigated for use as such. In November 2017, it completed phase III clinical trials for treatment-resistant depression in the United States. Johnson & Johnson filed a Food and Drug Administration New Drug Application for approval on September 4, 2018; the application was endorsed by an FDA advisory panel on February 12, 2019, and on March 5, 2019, the FDA approved esketamine, in conjunction with an oral antidepressant, for the treatment of depression in adults.Society and culture
Names
Esketamine is the generic name of the drug and its and, while esketamine hydrochloride is its. It is also known as S-ketamine, -ketamine, or -ketamine, as well as by its developmental code name JNJ-54135419.Esketamine is marketed under the brand names Spravato for use as an antidepressant and Ketanest, Ketanest S, Ketanest-S, Keta-S for use as an anesthetic, among others.
Availability
Esketamine is marketed as an antidepressant in the United States; and as an anesthetic in Europe, including in Austria, Denmark, Estonia, Finland, Germany, the Netherlands, Norway, Slovenia, Sweden, and Switzerland.Legal status
Esketamine is a Schedule III controlled substance in the United States.In the 1980s and '90s, closely associated ketamine was used as a club drug known as "Special K" for its trip-inducing side effects.